The present invention relates generally to electronic devices and more particularly to portable, battery operated electronic devices.
Electronic devices, such as radios, tape recorders and computers very often derive power from a battery source which is removably mounted within the housing of the device so as to enable the device to be handheld during use. Conventionally, two or more primary batteries, such as carbon-zinc, alkaline or lithium batteries, are arranged in series within the housing to provide the power necessary to operate the electronic device.
One drawback of electronic devices that utilize primary batteries is that the consumer is forced to continually replace the used-up primary batteries with new batteries because the primary batteries are not designed for recharging, thereby increasing the overall cost to operate the device.
Electronic devices which utilize rechargeable batteries instead of non-rechargeable batteries are well known in the art and are commonly used to provide the power necessary to operate electronic devices. Rechargeable batteries, such as nickel-cadmium and nickel metal hydride batteries, can be repeatedly recharged and reused for a significant number of charge/discharge cycles.
One drawback of electronic devices that utilize rechargeable batteries is that the consumer is required to periodically recharge the rechargeable battery, the recharging process often taking a considerable amount of time to complete. During the time in which the rechargeable battery is being recharged, the consumer is unable to operate the device, thereby limiting the range of potential uses.
As a result, it is known in the art for electronic devices to include a housing which is able to accept a rechargeable battery to supply power to the device but which also is able to accept primary non-rechargeable batteries to supply power to the device in those instances when the rechargeable battery is being recharged.
In U.S. Pat. No. 5,153,495 to Connors, there is disclosed a convertible battery handle in which an extended end cap contains a drive spring electrically insulated from the battery circuits to physically hold the rechargeable battery cells in proper position and a coaxial helical spring electrically connected into the battery circuit. The helical spring has a length insufficient to make electrical contact when the handle is utilized with a rechargeable battery pack, but when a pair of non-rechargeable dry cells are positioned in the handle the electrical circuit is completed through the spring. A safety diode is placed in the series with the electrical circuit for the non-rechargeable cells to prevent inadvertent charging of the cells.
Electronic devices which are adapted so as to be able to receive power from either rechargeable or non-rechargeable batteries typically configure the non-rechargeable batteries in a series connection within the housing of the electronic device. With the non-rechargeable batteries connected in series, the output voltage of the batteries is limited to the sum of the voltages of each individual battery, and the circuit current remains constant through each battery.
One drawback of an electronic device which derives power from a power source comprising two or more non-rechargeable batteries that are arranged in series is that the power output of the battery source is limited by the internal resistance of each battery. More specifically, the current capability of the electronic device is limited to the internal resistance of the weakest battery in the power source. As a consequence, it has been often found that the current capacity of the power supply is insufficient to drive higher power loads, such as handheld computers.
Various models of high power load handheld computers are sold by Data General Corporation of Westboro, Massachusetts under the name DATAGENIE. These types of handheld computers are designed for application-specific data collection, such as keeping records of inventory in the workplace. These handheld computers typically include a wireless spread-spectrum radio which is integrated with a laser scanner which requires a high power load.
High power loads such as handheld computers require that if a plurality of primary batteries are used to power the electronic device, the primary batteries need to be connected in parallel. Configured as such, the current capacity of the circuit is dramatically increased. As a consequence, the increased current capacity increases the total power output of the circuit, thereby enabling the power source to drive higher power loads.
It is an object of this invention to provide a new and improved electronic device.
It is another object of this invention to provide an electronic device as described above which comprises a housing shaped to include a battery cavity which is sized and shaped to accept either a rechargeable battery or a plurality of non-rechargeable batteries as a battery source for supplying power to the electronic device.
It is yet another object of this invention to provide an electronic device as described above which further includes a battery circuit for supplying the power provided from the battery source to an electronic circuit in the device.
It is still another object of this invention to provide an electronic device as described above wherein the battery circuit configures at least TWO of the plurality of non-rechargeable batteries in parallel.